I agree with ALOT of what you said but the market has been heavily manipulated from the start and one person (or small group/supercpindevs) owns most of the coins. Maybe it's not a scam but it is certainly not innocent.
Every market has manipulation, there are always person's who play the markt. As the volume is little you only need a little amount to manipulate the markt. In fact I could manipulate the markt right now. I could dump coins and let the price drop by half or I could invest 1 Bitcoin, that would rise the prise by 400% right now.
The question is, is the dev manipulating the price? I have not seen any proof of that. You can suggest that he is releasing slow on purpose so the price hits all low just before suddenly releasing a new feature. My opinion is that scammers want to move as quickly as possible so that tactic is not something I would expect from a scam dev. Second, you don't know for sure if the price suddenly will go up if the new feature is released what makes this tactic very unappealing for scammers.
It seems that a lot of coins are with only some people. But one of those big, if not the biggest bagholder will be Bitrex. A exchange does not keep your coins in seperated wallets! That would be to complex, slow and expensive as there is always a fee to be payed when transfering from wallet to wallet. Your coins al end up in one or a few Mammcoin wallets. The exchange just keeps records how much coins are your's.
In fact when you exchange them for Bitcoin there is no transfer. The exchange just say that now you have Bitcoins instead of Mammoth coins. It's only when you extract coins from a exchange you can say there was a real transfer.
The fact is that exchanges are a big problem in cryptocoins. MTgox will be remembered for a long time if not for as long as crypto currency exist. They are in fact the weakest spot in the whole system. But the good side is that when we start using Bitcoin as a replacement for fiat we don't need exchanges any more so the problem should resolve itself in time.
And people keep a lot of coins on the exchanges. Just look to the Gox stories, the ammount of coins people had stored there is often unbelievable.